﻿#region License

// Another free, open solution by folks who get it.
// Copyright © 2011 Business in Unison, Inc.
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#endregion

using System.Linq.Expressions;
using System.Reflection;

namespace Patterns
{
	/// <summary>
	/// 	Defines extensions for expression types
	/// </summary>
	public static class ExpressionExtensions
	{
		/// <summary>
		/// 	Gets the name of the property.
		/// </summary>
		/// <param name = "lambdaExpression">The lambda expression.</param>
		/// <returns></returns>
		public static string GetPropertyName(this Expression lambdaExpression)
		{
			Expression expression = lambdaExpression;

			while (true)
			{
				switch (expression.NodeType)
				{
					case ExpressionType.Lambda:
						expression = ((LambdaExpression) expression).Body;
						break;

					case ExpressionType.Convert:
						expression = ((UnaryExpression) expression).Operand;
						break;

					case ExpressionType.MemberAccess:
						var propertyInfo = ((MemberExpression) expression).Member as PropertyInfo;
						return propertyInfo != null
							? propertyInfo.Name
							: null;

					default:
						return null;
				}
			}
		}
	}
}